1. Field of the Invention
The present invention relates to a method of manufacturing a chip resistor.
2. Related Art
A chip resistor 100 illustrated in FIG. 10, for example, is manufactured by severing in longitudinal and lateral directions a chip resistance substrate which is formed by: coating the upper surface of an insulating substrate 101 made from an insulator such as alumina ceramics with resistance film 102; and providing conductive strips 103 having a predetermined width on the resistance film 102. The chip resistor 100 has a predetermined size in accordance with a standard (e.g., 0.6 mm×0.3 mm or 0.4 mm×0.2mm) and predetermined resistance (e.g., in the range from 1 ohm to 1 mega-ohm). The resistance film 102 and the conductive strips 103 are formed by screen printing or other methods (see JP-A-08-204063, for example).
However, as the chip resistor has errors of resistance in some cases, its actual resistance is set at a lower value than the desired value. As a result, fine adjustment is required to be made for obtaining the desired resistance by irradiating a laser beam to the resistance film after dividing the chip resistance substrate into discrete chip resistors to partially remove the resistance film. This process lowers the productivity of the chip resistors.
Moreover, while large numbers of the chip resistance substrates are produced at a low cost by screen printing or other methods, processes such as adjusting the film pressure of the resistance film and controlling the amount of conductive powder to be mixed into resin constituting the resistor film such as carbon powder to control resistance values are required so that various chip resistors having a wide range of resistance values in conformity with standards can be produced. Accordingly, it is necessary to design a wide variety of resistance films and also control the inventory and manufacture of the chip resistors for each type of the resistance films. This also lowers the productivity of the chip resistors.